Field of the Invention
The present invention relates to a windshield of an aircraft, and more particularly, to a heater provided in the windshield.
Description of the Related Art
A windshield of an aircraft includes a heater in order to prevent occurrence of fogging due to a temperature difference and adhesion of ice (Japanese Patent Laid-Open No. 2011-225076).
In Japanese Patent Laid-Open No. 2011-225076, a thin film of ITO (indium tin oxide), gold, silver, or the like is formed on a windshield panel as the heater. The fogging of the windshield and the adhesion of ice thereto are prevented by heat generated from the thin film to which a current is supplied.
The windshield of the aircraft, and the heater provided in the windshield need to have reliability against lightning.
Countermeasures against a direct strike of lightning are taken such that a high current of lightning striking a frame or the like of the windshield is spread to the airframe which is a conductor. It is also necessary to take countermeasures against an induced current flowing through the heater of the windshield due to a strong magnetic field in association with the lightning current.
If an induced current that is induced in a conductive film or an electrically-heated wire provided in the windshield as the heater flows into a controller connected to the heater, a voltage of the controller may be increased beyond a withstand voltage.
While an electromagnetic shield is typically used for avoiding generation of an induced current by an external magnetic field, it is difficult to ensure visibility required for the windshield while providing the windshield with shieldability high enough to block the strong magnetic field in association with the lightning current.
An object of the present invention is to provide effective countermeasures against an induced current that is induced in a heater of a windshield in a lightning strike.